SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'de48119027fefe0d1b4e3313469d1da2bd72db4525a2f5f182f2b78e651d1306' 
  AND token = 'SzJ/09NchcLiL1YwbTNLoQARKuqhCeJ9jPWNG1uwuLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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