SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e6ab20460f5a9cf2501b3cf98942482c50bac759880a9af4e57c11f72462749' 
  AND token = 'JCHm0fyYfiIs566j1nI3qoOCvQaW/6bzkuqX+pVka/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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