SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53c09b800c532adc0330414688eca9b70827c883a6e5d2c49a58041dd5db74a7' 
  AND token = 'AKBzfToMZ+78nSeg59AulYboRndBsGq+oxhSgXnjI/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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