SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39fc1a06c418796f4f7ec2ad8b53de3fbe1adaa7dd9654613210a9959971c592' 
  AND token = 'DbcvXcrRsHazZzF760yrrf9JEDK/xWOgksFKvoGOXyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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