SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9643a520048d77d3143cdb8cb93880d3f208b62933624e28dec46eefe2aa8341' 
  AND token = 'fR27sRLRiav4Nw48amFMLve6DDK7ee/QKglOdGB3Pmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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