SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c2934629a9020660232db787595a5cceefedf77db6e2b4c517567760d509fa1' 
  AND token = '1rN4IFeUrJf5+tSVHFNKAFH7M3NMAUrhGTy7Jrmgf2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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