SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cfc1778fc03acab2167dea92e1cfb4dd6f176409a632edae88f95e2dc5a28a1' 
  AND token = 'xzUj/mGsPhyk6YEvjeNNQWCUf30jOBhKqzFyjE+WbcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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