SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '270d20a1af37aab689abd79518fedb0b6d5921e7d6f09cf56550aa7f5c3e359b' 
  AND token = '58G/s5K2hPFrCkqVicXRdL4ZZHlDYa3qfUgCbwiggPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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