SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dee4d35436a0aedf49dda0dec06dc93dd84503bf7af2f6c6af866b1acfcad06b' 
  AND token = 'c6BHvxpH8lahj2OqjkXp2GASQkMbp/caF6BMYwbq2Pc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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