SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87fcdb15ca31a0d9ead39a1447ee3d5f69a111aa26f2acc6447be646302c9868' 
  AND token = 'vvKflSURpPQucwg9m1f9l3IQSOiyCnoIf0vQog3JZ0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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