SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9be280d599e0414a66c269b7342409b85bb4eed1f6a67ab5a69df40be00308cc' 
  AND token = 'trt8IqtRT8GMDwjHgRH+JmfJ5Ydo9Qjoe5p2llA52lM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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