SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec53c7ab11ff933948079f830316ea3f2dfbb015979e9a2a24086446d9fbf9f3' 
  AND token = 'PPrcJuume+pUhYznbFEIHWDrV5gHCJchACKPjEF0yhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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