SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9731021f70eb54d5544473a22e50ca88479199acbcd30939f8cbe951718e0be' 
  AND token = 'NkKDnFctB/qQ8QzXhNIIf2EuyEh+PKOClG8cleglnr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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