SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '862b36030f4d0dfd9829b83d657769ddd799eaeee6d682a1075fe2e2c245c10d' 
  AND token = 'h3H0kuCcnaD7MY77L3DNMWobJcKSkagmyugYv44OOdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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