SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ead0a88f69310dad3589ec4f55a11c62cc137637699ddc552a35784a1fb165f9' 
  AND token = 'c8wMW74IqYr9G2mJJQ2KC+GnYVi5AcDgouz2YE/tFPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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