SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5abb55a5749649475e8450ef4db9bd655a16e1c0d368c8cdba9af1791519a7b6' 
  AND token = 'JnFboMPoVVFTaTqe2FEbAS2Msjf92RFxhGo/e2HAQHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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