SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8ade15b7b232795319e89bddb4d5e47cec7425b392a300a68784ef255fd1ecb' 
  AND token = 'wULRSp+IWYTXrJzhK/3BubEl+Wu01wl27IKMvePZ/LU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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