SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3abb92d267980ab96200326d2ec7630794806f281c5a83f93b765f423955907' 
  AND token = 'S+eISpFqfDzghNK5S8XzZujA5wEA3oUMqL4I+Q2dlTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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