SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '598d9fbc1f6b0e9d08722846cd39c28347ab47666085b24877015c757b5d0673' 
  AND token = '8R1DJjyqXKObp2i0WiscuxWx7AcjOF9BsvUTXZkQYng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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