SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57aa17164066dc179b123bbd60ebd44988b349be5b3d2c007e281ac4260be152' 
  AND token = 'fzrv1PZPoYWDKjAoHEd9GRPK323cBQ58falSrS7Bs5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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