SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4da6600e6c5bd99a7caeca1f484c65a8fec2f1e6d49085903997ae45e4a6e852' 
  AND token = 'ZkMIjxYz2YglqMmBQlkmEEuUZuhxXwcEVwBqgcgv5bM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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