SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7df046809ec300a2f5a27205b73d23306a58eab67537872cf99d55483a2b3f6' 
  AND token = 'jwwivZz3EkSboSRiPF5YFIdRdz/DvckeDzMkIkRg0sQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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