SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e461693c2bf46da3d0d632973023d66fa06c6f89019e39b7c041c3305fd89699' 
  AND token = 'dPb1+8wwprqEjXngzDDkA7K/Ar8B7ibYdGPr7YxpLQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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