SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd5ddc9852ca0d116a0292dba0170b7037456f65fc72ac806e36d3d208f9de94' 
  AND token = 'Ac5aCI/TBHfxuUhyvjVMH3GGnDwuvQjjCfBw2aeiVUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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