SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd49d983b73342f603c78569e7c6cb29aff23c8e08c8d2e62ac95de1008b8a780' 
  AND token = 'vlhCj7P/GpfT0oYjp/VF1a6b+zdZVl77IUKMuH+2AdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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