SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fabb01b0c485fe233c11176934d267f5b4505ff1f5c7783c820746f03aa9c6b' 
  AND token = 'YlvItID+wAMIhcTPbZ9dXvt8dyP8TqJQAM7zW8VSmH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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