SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b55622585bba209667a9d62ae1cc84c757f795fdf3911c0c4ef520b5f03a8b6c' 
  AND token = 'CrxqWWqWRELxk65fQPF3JVMWW7Pa7pAWs8YTv5NQz9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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