SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c6de5c6bce130d8ae680afbe7431f75d35af28b841729cf5749e7c8969eb04a' 
  AND token = 'ZaGQbOQzXQJfElYuErhAAsBF2tKxzsq/1sEBKlrJOmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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