SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7722d576e53b868a593f6a3239831092036e928cbe3a39041f1cc2f5f69ab9a6' 
  AND token = 'fXkMykkunsiPZSeMfcIdt7eQ2Qd4CletYkAiLWBo0Cc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}