SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78da1c7caa37a0828f850b9a1beebc90ebec6949231367c717b10939b159e41c' 
  AND token = 'Bdp0bAA6d5lj1PV6wXHIXFKojpJc1nZOjtqivgXnYYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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