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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '947fde75624f9aa1dca195932efdef10a42791e5b570cde1e6abcd3803b1cf39' 
  AND token = '4iJpo9f0ZciEEChc8SyXUJLInwawvJdA0YO1E77OMPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}