SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '793f32c5a081d48fcd43ab797bfad6727a1ec0637ed60c1c696b11844d667aeb' 
  AND token = 'NP761jsqEx3awdz9LjgwdNyxRqvyyS1bbHrhXTK5ugM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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