SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c765aa694427e772600a1659a6238809c5f7e3b3add77424b3a5cd7977aa24a' 
  AND token = 'BSNCVjPo3AlE1KoJ6tKdsjqvbgnCYpIhlRv3PSCmrQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}