SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '068ef9629ec3f90d2b30e5f86b982501639b43a484600a05e8118c2fb26e0850' 
  AND token = 'Wc5dDawKwb861Ig4oxdDUP7MRyjpUY7VlEFLtojUMEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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