SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b830a1c5944874ea170109bb706a45236b46ccdefb18f3a762d9c75ad7e852db' 
  AND token = '5b/t9dka6F5zFckDsR3Vizy5KgQ5BD3egR3+Q1e8Ufo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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