SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9684d16c0e9ab3b0061bb71e65a6e7050dbebcb29aa12cadafa37d2e4118df6f' 
  AND token = 'rk2AYIbiioGW4VlllOqn70xmi2p4JjN0WO7uxeyteGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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