SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '384452e4c16e1399e102887adb37e395aa3f40b8c32f681c9f85d9552f180961' 
  AND token = 'ih7ovcKLuPsQg+YjxbOAsJL3bkqb40nmvjQprkJyPiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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