SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e949ff7c019d32c06a3a3750e2231c305ae0b93ba2061bd239d810ea842885e' 
  AND token = 'v6ir2FGDVontjPq20Pxp2AQ1Ct5srPwjl8hE7D83988=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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