SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d6e6e5c7d35dfaf093216bcba5aba855542cd23aeb9b0346635ac414c1b6de9' 
  AND token = 'rPREId7OvtnTjjl9iTn4yzFtFxg7Zj38mYIluH81Vkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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