SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f8c5d8383983e5a8e99c12575ea82b1914c8635669589d574cacb7281f90556f' 
  AND token = 'n2U9cuZq1/7Pm5YwCQa4kjvAjetZKy3jUCl/525bzhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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