SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7134f256537fc03643b8e45495f3f6cd63262b396193984b13e3e7208b3fe559' 
  AND token = 'A3tArMzusStERpvOMwh2A6Dyfe+GCPbQDOmY4ZnPKA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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