SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c193f622f0b1126155e298f5c6c32e927c7edafce2b5364317a1580fb476413d' 
  AND token = 'TOG7JRokcSalThyr8xPWUkcRs8agUuTEu4rKfX5r0vA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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