SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3759aaa7594f1c3848e6124841a5cb94bfb4af28da95f68846a674323cc0a608' 
  AND token = 'BROS8wC7NybUyJ+4LHK/D7Wj6wjZhSGlDDyi5BfVRgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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