SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e5fd1b51a4c926e5be3b163ccebb9eed0ea810ee52b5283e48dfc359b9c16e46' 
  AND token = 'R0mxCtbalw4Qu2fsgGfsDhYvMku/4XvHYF9qb7ZetDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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