SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9054883ccbc0d26d6c543df73030478468e6cc930a63e0e17356295d571c3bb' 
  AND token = 'AdLZEvTeQsGmwDd1nLejycDRf4T3YUHRvlJIY8h78lk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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