SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2da36928363903593e4b87b274d71bb9d8801e382f36655eea7471673a201a91' 
  AND token = 'BfrQA98ur1MBSHEsBee4QIEt/QzSs2wulW8IsexrSxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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