SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '898bb2d686a411a64267d022ec2225dfc575b8cbd48b1a509ab8da771c631554' 
  AND token = '8tj69rXkKTIy+EU3WhebEsRjS2/MnjFofaGndJ8IsTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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