SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08f4ab9015535fb8920d908b529062588eac27e0aec3db80af7d1d35003dff90' 
  AND token = 'C7Kd4WOrgcIlqpxhlJvmNz83MWjSArUsY05ka2ULCDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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