SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8328591c0ff88831242ea1b8261206db8f26b4441a8656fe4457962a568b32e7' 
  AND token = 'eNwxeOHX/W2W98Oz0CMQdbkg+SHNdMIeYCZSwpsy7aM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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