SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ba91963318d3ba07d6f3978becf57211cb78bd54ec7f9b79db9b31925ff92ad' 
  AND token = 'JRNu+0H9ZwNI2GocaFnj0owIS903WBv0HdlGp/pNsEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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