SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31b8193dc3f187c4ba7c8f6ab344dc36fe4f8ba192dbaf3269a45586b2a2349e' 
  AND token = 'O2soUhqvroxc7pwoQxQmOZcaVOtzcvGr9NEpMYJC8VY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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