SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a770f56f52c59798d0023d17fa8bcb68edbf0caae514f636d00746fc63232455' 
  AND token = '5Q4+ofB/d0/ESbouq0mF++IvT9JyhxkFJienH+2RH50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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