SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2debdf03c0a8952a2ae83af48f6b1325d3380220b2b94b7a83e671516b2d268' 
  AND token = 'vsq1GbPS9aPUzkRLP56uAJUza/5QxgTmTQJhtn+gPhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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