SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71ba7908e869b5bf65bf99d488bdefa647331cbc0a03d39af728e4fb0a6dd7a9' 
  AND token = 'J1FQuQAIKBLCildbUycsC5+tbgHzUwymcsvJ00yYLMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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