SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a121bc7cc07cb7096654d48f447735314e4c202f14d9d131b16c9a0cd835596' 
  AND token = 'yc/Ax7IL8UTnzVo/fRGKHkiXzasunii7GKerCN1bAOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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