SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c948b920e279ebed4818d665cad16920fdf98cba0605287e85bb7a24ca2693f' 
  AND token = 'k/Bt3vWFN8dfhPy+3tb3cDN5wODk4wY+Sq1/CPlBJP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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