SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28a288ff8eae78ed829e695b4e633527e4d306eeba7fa57dbc7651d06c6eb85f' 
  AND token = 'VaRavw9P12897qIdxOafNJsZTXkzGmhoGkdpCPCjs60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}