SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '978ff8bceae2280ee0aa936c52ddc0024b1441136991d87b1f8e46690429708c' 
  AND token = '5zlGsUjf43Zt55RfyvPWB/r8ObO0quSayHWxGLVqz+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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