SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dff3053e93a4451811d57418aea4bbd62591b516b4910fb547d02c9ad1c95bb' 
  AND token = '6kDfw/f10rdUMpBUqIGUOxV3DatiM9RLP26hWSnZjHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}