SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b89e249048a9df50f2bc2c346b08330315b57b236bc44519dc258f0585eb912' 
  AND token = 'F66yXQjZ+KWQtIdj7ziAG2V/FptFemWSDW6UF4jmUtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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