SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7e93116cb981badcbf95414b45882b4bc92709a9bd5740dd70b0e44c798dfe7' 
  AND token = 'JSJ3M81z1YcRsos+KtI8UNUlocH9nGkiMjAoC9SKmcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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