SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1f5bf2830055e0e57bf63ec1e06e3df3e140f0eedc41a150708959efd8806c55' 
  AND token = 'wRDLlrZFFJCVn4l6tEia2O611QDJ5lvM47SatyQwwTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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