SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44af9b36bb93c1bc55eb857fd22dbd9a287b5546827d0d610ca440e3d22f7c74' 
  AND token = 'M8OHkJwqnCG6j3QU0j1lpETtIcTyp/iNzK/ufZpUdEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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