SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e4e42d513125f6718cfd06bcc3787ab995a6a5d5e33d4c094c941839f0bec79' 
  AND token = 'P9z283uRWNRqKYe7xiFBx1o5hv/Mx83YNFBwfb8Sbgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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