SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8aab175d4d317a505f1f5424e46a0e0af250174a63a91a04dc3d74897be9a3fb' 
  AND token = 'LuSERR7jIGyhQh86noFRv5fEduE8d6H2PsNjyF7KopI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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