SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c962701f6aabd0ca66e34c051f6d7061bf2d4bddd4d4dbd8644e12bedfff85e' 
  AND token = 'WRZF206tpmP9xgmFvLb39WXMXZtyN0N8gYf8DtMQhbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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