SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6cccb0259461f4fd6ccd2d72b93a352d45f315b210e55ca465a454d3a0ab255' 
  AND token = 'Wf6SQb6Li7Qf7EvW5xEcBuu3LAMBgYD6MCVw1gezHys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}