SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6f304c71054c2cb2d5573eac7a581dc7b4a6fba02cc3919abf95f6e314b0b76' 
  AND token = 'nC9jFblp13BV4pkcrQ9N6TMpEANle6/XRgixs5YHxLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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