SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37b03a7f9518965bd7937278bb8ef0ffc615d08a23453689fdc9c354d44f8b46' 
  AND token = 'fE5w1XxXMSThQihEZQytszrqo5WFw2S7Xlyn+Eb9IFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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