SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c13c703c22dd751febea441118356d075e16a013d70d28fcd5a75a414a4a978b' 
  AND token = 'vqXSwdhwKZwoostMT3ZbQ2xdrKJ56KUPmjs7A7tQJWQ=' 
  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"
    }
  }
}