SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4cdb685ac9080d86c316340aab47be3f293e0794ed8afcf586a474de4dd3116' 
  AND token = 'DSO3l1h/TMmnIHJN65d/vjwr/HbC+jHcDYDBWzoViOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}