SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27bae50d791a58abbf09544a5c85108bd2a88599acd69b754d70969fd2a18fd8' 
  AND token = 'VL9rYD6IwPUDCAmsXAR7kSTHKMRs1o02zO4qxYhkDoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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