SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4117161d525b7b9ec690b35423b18b8381acd1f057b98fb82b48e4543bdb5c9' 
  AND token = 'GppqykrhFeWEdK+vgulLdZLKzYe0Q0JtT2l0cvg5rRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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