SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afcfa8b4f56d1b3bb56976231b4bbc90f04976d3abb981cf4b02ba70594f6760' 
  AND token = 'PLDef92r6teZLQG+Pq4dDqdTuzJGiEkmZuAHmPHQdCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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