SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2735f58666f97fc098043c7a298de5b6ebc583a1a9329bf267b9fbfbf17cba5b' 
  AND token = 'hxLeuFZViZfZ8G4SEFGQogOsRA8OiEpwSg/YE43Gqqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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