SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f705bbf4ea4829cdc76e2b1ea9b1aff1ba31791ecb5e4ec6d3a78ca86775fed' 
  AND token = 'lPmEqHLQisOjrjVLU4naKPzbS/kX6FaWFi52kEXqql4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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