SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16681b8463551dd3fd52b6bb9a903d32c6eb0bf574f1e3ef13b9fd619d5a21e8' 
  AND token = 'WrKbDqqsfK4rzB29aSTNLMPcO4kMqdikl/OPfEOQ2qw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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