SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a6ed98610be8fc7a32009486deb2c7d1e9cca93922c18e1c2c831641a9dc83d' 
  AND token = 'XxERTRTNHZCoLKDqMxlDnbLR+guv9z5n9szydyuVAcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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