SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d4b70561b155481c4dd7ddcd5b236a2865ae3f7c095c61ff1997d1b026d2044' 
  AND token = 'f+BoqgI3jZxCI+Yux+mdlkDRp9n0PVWZ8PFwQTKGLHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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