SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd15a681272a9efc26ad6bab2f92569ac633cae1045652d29590dcfda84c0e2a1' 
  AND token = 'szibxIjsbmjLysKzTJ9Mdvw/pX1a/CFXRRoGHACaXP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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