SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3afa05d8b3a11c8f4546f5e4cb5e9ae88b929ea2631ac0a68be5c818c0b83c9e' 
  AND token = 'OzEZvb6hK2/eJ2wwOV3S+MmXNI9yduETSf1VPbDboC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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