SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d9296ba66adb3e4649c556fe473e8d0ed28543bfa0df0b1950aaad7570a23e1' 
  AND token = '+BvzItt18fxSvOJPqwoMKg8+ltGBKBDoUMPI8I2RboA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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