SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ec9d9632142cbc3d32c4651dbc6ff2506fb7610a759bd9875d575729fae3d89' 
  AND token = '/EXVHY/BZpRRVUPNfPZQj1xDupTReJFoJ1ZVHK/rjck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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