SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4abe2adfc2f2bc9314a99b3600683b95a55f5c18954c47be5249e985557b876a' 
  AND token = 'QXh/VQcCVlCu77CtazSFtAzBcWU4HS8qJ6uBJLY2i1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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