SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfaa8b5f640fff53d4e2f6007fa85c1cbd73af0f318c2d472a12cbb0a6018e38' 
  AND token = 'LJLTgP6ZNUo4dZrXVCoReQi9cVV/cmS6miA/UEsueZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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