SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1e1c4297c80fbbfbc53c090e2d6cb9e13d66ef4bcf470551b4012dd8a827de7' 
  AND token = 'emClkALzBWhTnqTS/pHF69ICkH+NPX/INTRP1oIoUA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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