SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ac2a1ce7de0c65cdb876164c36d6937dd939adf46c356b2b09d957a3529018e' 
  AND token = 'PnP8TefDIXntqOnFeVd6bpqrw86qUcdU3P+fexTemSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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