SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43fb81e75ada9de96337092ec024a7b0b56aab87b7dd82edbf67ff8019486373' 
  AND token = 'LxbvkgZ5RbQYS46scbKLqREJ2iWfalsjLPz76LG/v+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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