SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '621dc6b06ffa3409220673c5ae1c10c9767cb3e670fbc7096b63e36574e64aae' 
  AND token = 'DAfFD1W8R6YToVKkh7C2l3yUuW5XmB9/9TOIWqG5kI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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