SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7778ed490053114828b6ff32ae72fd613c1aebf9fa4a51d52a30b7bdb9db957' 
  AND token = 'lbjami6+YiarZuS6Xzrweq6N5LpfSiandINPMW5p2kQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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